More review Flashcards
decreasing slice thickness does what to partial voluming
decreases
what performs phase encoding on coronal images
X
what performs phase encoding on sagittal and axial
Y
what performs phase encoding on axial images
X
What is the approximate T1 relaxation time of water at 1T
2500 ms
What signal intensity is an area of abnormality likely to have on an ADC map
Hypointense
SSFP sequences usually produce images that are ___ weighted
T2
what is Nuclei give up energy to the surrounding environment, resulting in longitudinal recovery.
spin-lattice relaxation
aka T1 recovery
In which direction does chemical shift artifact occur
Frequency Axis
what increases T1 weighting
short turbo factor or long turbo factor
short turbo factor
What does the slope of the frequency encoding gradient determine
The FOV
The size of the anatomy covered along the frequency encoding axis
How is K space filled in Fast Gradient Echo Sequences
Centric filling
Keyhole filling
What signal intensity is an area of abnormality likely to have on a trace (ADC) image
Hyperintense
What is the most common material used to make permanent magnets
Alnico
The anatomy of white matter tracts can be mapped using strong multi-directional gradients by use of
diffusion tensor imaging (DTI)
When using MRA to evaluate intracranial vascularity, flow within smaller vessels can best be demonstrated by
3D Time of Flight MRA
no power supply, Bo is vertical
permanent magnets
can turn off/on, Bo is vertical
resistive
high SNR, Bo is horizontal
superconductive
type of contrast agent may be used in MRI lung imaging
helium
what is available imaging time equation
R-R interval - (window+delay)
